1. Field of the Invention
This application relates to an oscillating device, a method of adjusting the oscillating device and a memory.
2. Description of the Related Art
A memory is provided with an oscillator to generate a self-refresh request signal. The oscillator creates variations in the cycle of the oscillation due to process variations. Accordingly, the refresh time required for each semiconductor chip differs from each other. In order to solve this problem, in a probing test, oscillation cycle measurement of oscillators for self refresh is conducted for every semiconductor chip, and according to each cycle, the frequency division number is changed for every semiconductor chip, so that the generation interval of a refresh request signal needs to be adjusted. By doing it in this manner, the variation in required refresh time for every semiconductor chip is reduced.
Japanese Patent Application Laid-open No. Hei 9-171682, Japanese Patent Application Laid-open No. 2002-74994 and Japanese Patent Application Laid-open No. Hei 7-220473 describe a semiconductor memory including a oscillation circuit.